1. Field of the Invention
The present invention generally relates to devices for attaching towed loads to vehicles, and more particularly to implement connection devices which allow an implement to move independently of the position and orientation of the towing vehicle.
2. Background Information
The typical manner in which farming implements are attached to a tractor is by the use of a solid draw bar which is rectangular in cross-section. The draw bar has a hole in it through which a pin is placed which holds an implement in connection with the draw bar and the tractor. The implement typically has a rectangular piece with a hole in it through which the pin is inserted, or it may have two rectangular pieces, each with a corresponding hole, which are oriented with one bar directly above another bar. In this configuration, the draw bar of the tractor slips between the two attachment plates of the implement, and the pin goes through all three holes.
The problem with this arrangement of attaching an implement to a tractor is that this type of connection is either built with a lot of slop between the parts, or it develops slop as the parts wear against each other. When an implement connected by the typical connection is pulled behind a tractor, for instance, the tractor pulls it forward with great force. The force is transmitted from the tractor to the pin which holds the implement to the draw bar. The implement also can be resisting movement with great force, as plows, discs, scrapers or other implements work the earth behind the tractor. This results in great force being applied to the pin hole in the draw bar, to the pin, and the pin hole in the implement attachment bars. The holes get larger and larger, and the pin gets smaller and smaller. After a period of time, even in normal unstressed travel, such as on a paved road, the slop in the fit between the locking pin and the pin holes causes the implement to bounce back and forth and to further enlarge the pin holes and to further wear down the pin. This jarring and bouncing back and forth also causes damage to the implement itself.
Sometimes the amount of play or slop in the connection is intentional, and is built in to allow the implement to move in a plane different than the tractor. For instance, when the tractor is on level ground, but the implement is on a side hill, the connection must have enough play or flex to allow the implement to twist in relation to the tractor, or the connecting parts would bend or break.
Some manufacturers of implements have tried to address the problem of too much play by placing two pin holes in the draw bar, and using bolts with washers and nuts to secure the implement to the draw bar, instead of using a drop-in pin. This approach greatly improves the wear and tear on all parts of the system, but it is slow and awkward to attach an implement in this way, and requires the use of tools.
Accordingly, it is an object of the invention to provide a system by which a farm implement or another towed object can be attached to a tractor, or another towing vehicle, in a manner which does not allow the pin hole or the pin of the connection to develop excessive slop through wear.
It is another object of the invention to provide a connection between a towed object and a towing vehicle which allows the towed object to orient itself according to the terrain it is traveling over, and independent of the orientation of the vehicle towing it. It is a further object that this connection system does not require the use of tools to make the connection.
Additional objects, advantages and novel features of the invention will be set forth in part in the description as follows, and in part will become apparent to those skilled in the art upon examination of the following, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and attained by means of the instrumentalities and combinations particularly pointed out in the appended claims.